Coordination polymers with the chiral ligand N-p-tolylsulfonyl-l-glutamic acid: Influence of metal ions and different bipyridine ligands on structural chirality

Four new polymers, namely [Ni(-tsgluO)(2,4′-bipy)₂(H₂O)₂]_n·5nH₂O (1), [Co(-tsgluO)(2,4′-bipy)₂(H₂O)₂]_n·5nH₂O (2), [Ni(-tsgluO)(4,4′-bipy)]_n·0.5nH₂O (3), and [Co(-tsgluO)(4,4′-bipy)]_n·0.5nH₂O (4), where tsgluO²⁻=(+)-N-p-tolylsulfonyl-l-glutamate dianion, 2,4′-bipy=2,4′-bipyridine, and 4,4′-bipy=4,4'-bipyridine, have been prepared and structurally characterized. Compounds 1 and 2 are isostructural and mononuclear, and crystallize in the acentric monoclinic space group Cc, forming 1D chain structures. Compound 3 is also mononuclear, but crystallizes in the chiral space group P2₁, forming a homochiral 2D architecture. In contrast to the other complexes, compound 4 crystallizes in the space group P−1 and is composed of binuclear [Co₂O₆N₂]_n⁴⁻ units, which give rise to a 2D bilayer framework. Moreover, compounds 1, 2, and 4 self-assemble to form 3D supramolecular structures through π-π stacking and hydrogen-bonding interactions, while compound 3 is further hydrogen-bonded to form 3D frameworks. We have demonstrated the influence of the central metal and bipyridine ligands on the framework chirality of the coordination complexes.